Preheat oven to 350 degrees F
Saute onions with 1 tbsp oil of choice (I used avocado oil) for 2 minutes, or until begin to be translucent. Add in diced chicken and cook on medium heat for an additional 3-4 minutes. Add in zucchini, garlic and Italian seasoning. Cover for 5 minutes, or until chicken reaches an internal temperature of 165 degrees F and zucchini is cooked.
Cook pasta according to package
Combine pasta, marinara sauce, basil, and chicken/zucchini together. In a separate bowl, combine mozzarella and parmesan cheese together.
In a 9x13 baking dish (or 2.5 qt casserole dish), add half of the pasta mixture. Top with half of the cheese mixture, followed by the remaining pasta and remaining cheese.
Bake for 25 minutes. Broil for 1-2 minutes at the end, watching carefully to make sure cheese doesn’t burn.